I had a great idea and wondered if there is a simple way to record the motions of, for example, my face and then map them onto a model in Blender? This would be really cool, if there was a free program for that or something similar...
Such a technique exists, it is widely used and there are free programs capable of doing it. It is called facial motion capture (or facial mocap for short) and vanilla Blender has tools for it.
A quick Google search found this: http://blenderartists.org/forum/showthread.php?243419-Facial-Mocap-Tutorial-(Basic)
Looking up "blender facial motion capture tutorial" on your favourite search engine should find you tutorials on how to do it.
you can check out OpenKinect I don't know if it does what you are looking for ti will capture body movements but I don't know about the face capture... but there are pay alternatives like http://www.faceshift.com/ that does it... or you can check out something like this https://www.youtube.com/watch?v=a_AwDv9Al28 with putting dots on your face like they did in movie Dawn of the Planet of the Apes ... just an FYI if you didn't know the Kinect method doesn't work well in sunlight that's why they had to use the dots but with the dots you should use it at high fps capture rate like 60+ the higher the batter and try not to drop the resolution to much... FYI a lot of action camera's like the gopro's have high fps... I don't know if that will help you.